Fluid transmission



Jan. T2 1943;

C. H. CRABBS FLUID TRANSMISSION Filed Jan. 24, 1941 INVENTOR. CHARLfs02,4555.

Patented Jan. 12, 1943 Charles .H. Crabbs, Dcnve per cent to Victor B.

1 Claim.

This invention relates to a fluid transmission device for transmittingpower from a drive shaft to a driven shaft. The principal object of theinvention is to provide a device of this character which willautomatically adjust itself to load conditions on the driven shaft so asto provide the proper ratios for all conditions of speed and load.

Another object of the invention is to provide an automatic,variable-speed fluid coupling which will pick up a stationary load onthe driven shaft and gradually cause the speed of the driven shaft toapproach the speed of the drive shaft, without the use of gears,clutches, or other mechanical transmission devices.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efliciency.

I These will become more apparent from the following description.

In the following detailed description of the invention referenceis hadto the accompanying drawing which forms a part hereof. Like numeralsrefer to like parts in all views of the drawing and throughout thedescription.

In the drawing:

Fig. 1 is a diagrammatic, longitudinal section through the improvedautomatically-variable fluid coupling;

Fig. 2 is a cross section therethrough taken on the line 2-2, Fig. 1;

Fig. 3 is a similar section taken on the line 3-3, Fig. 1.

In the drawing, a drive shaft is illustrated at It and a driven shaft atH, in axial alignment with each other. The invention is .designed totransmit power from the drive shaft ID to the driven shaft I l atvariable speeds and at variable torque, depending upon the speed ofshaft l0 and the load or resistance on shaft II.

The improved coupling employs a circular fluid housing, preferablyformed of two bowl-shaped, similar, half sections l2 and 13 asillustrated. The two sections are secured together in any desiredmanner, such as by means of suitable clamp bolts M. The fluid housing isrotatably mounted upon suitable bearings, such as indicated by thebushings l5, upon both the shafts. The housing is thus free to rotateabout the axis of the two shafts I 0 and II at all times. The twosections of the housing are rounded inwardly toward each other at theirperipheries to form a substantially semi-circular, in axial section,peripheral chamher as illustrated in Fig. 1.

The hnusin 'sectirm I2 is provided with a inr, 0010., assignor of fiftyGinsberg, Denver, Colo. Application January 24, 1941, Serial No. 375,818

rality of fluid guide vanes l6 within the inwardly curved portion of itsperipherm 'lhese vanes terminate concentrically about the shafts andparallel thereto at their inner extremities. At

outer extremities.

their outer extremities the vanes I6 terminate at the medial transverseplane of the housing. The inner edges of the vanes l6 are arcuate aboutan annular axis concentrically surrounding the shafts. The arcuate axisis so positioned that the vanes are narrower at their outer extremitiesthan at their inner. The arcuate edges of the vanes l6 terminate in andare secured to an annular curved plate l1.

A'driving rotor hub I8 is keyed or otherwise secured'on the extremity ofthe drive shaft l0 within the housing. The hub I8 is curved outwardlyadjacent the wall ofthe housing and is providedwith a plurality ofradial driving vanes l9, preferably corresponding in number and spacingto the guide vanes l6.

The outer ends of the vanes l9 closely align with the inner ends of thevanes l6 and are equal in width thereto. The inner extremities of thevanes l9 terminate in the. same medial plane as the vanes l6 and are ofgreater width than the Intermediate their extremities, the side edges ofthe vanes join an annular curved plate 20 which is arched about the sameannular axis as the plate I! and closely approaches the edge of thelatter.

A driven rotor hub 2| is keyed or otherwise se-J cured on the drivenshaft ll within' the housing. The outer extremity of the hub 2| is alsocurved outwardly similarly to the hub l8 to provide a streamlined fluidpassage. A plurality of driven I vanes 22, preferably corresponding innumber and spacing to the vanes l6 and I9 project from the hub Ill. Thedriven vanes 22 have a surface contour similar to thetotal surfacecontour of the two opposite vanes l6 and I9. Their outer edges terminatein close proximity to the wall of the fluid housing and theirextremities terminate in close proximity to the outer and innerextremities, respectively, of the vanes l6 and-l9.

Intermediate their extremities, the vanes'22 are arcuately notched toreceive an annular channel plate 23 of semi-circular cross-section.

The semicircular cross section of the channelplat extends about thecommon annular axis of the plates I! and 20v and closely approaches theannular edges of the latter.

Thus the three plates I1, 20, and 23 form a hollow, doughnut-shaped,bafile chamber 24 about the axis of the shafts l0 and l I. Each plate II, 26 and 23 moves as a unit with its attached vanes Operation Let usassume, for illustration, that the shaft i is connected directly withthe crank shaft of an automotive engine and that the driven shaft II isconnected with the propeller shaft of an automotive vehicle.

When the engine is started the driving rotor vanes l9 act in the natureof a centrifugal pump, drawing in fluid adjacent the axis and throwingthe fluid outwardly in a tangential direction from their t p It isdesiredto call attention to the fact that the driven rotor (vanes 23)has a greater diameter than the driving rotor (vanes l9). It will alsobe noted that the radial width of the annular fluid passage between thedoughnut-like chamber 24 and the inner circumference of the housing isless than the same width between the hubs and the chamber. Thisdifference is so proportioned as to accommodate for the increasedcircumference of the former passage, so that, the cross sectional areaof the oil flow passage will be substantially uniform throughout. Thusthe velocity of flow of the fluid about the chamber 24 will besubstantially uniform at all points.

The forwardly discharging fluid from the vanes I9 strikes against thevanes It to initiate rotation of the fluid housing. The contour of thehousing and the direction of the guide vanes throws the fluid againstthe extreme circumference of the vanes impinging the fluid there toinitiate rotation of against in an endeavor the driven shaft II. If theengine is simply idling and if the shaft II is loaded the fluid willsimply flow back toward the axis and again enter between the drivingvanes without imparting rotation to the driven shaft. If, however, thespeed of the engine is increased, the impinging reaction on the drivenvanes increases until a point is reached when the shaft II will beginrotation in the direction of, and at a slower speed than, the shaft Ill.

The transferenceof power to the vanes 22 by the impingement or velocityis assisted by the fact that-the rotation of the housing, through themedium of the, guide vanes, causes a centrifugal increase in density offluid at the outer circumference. Since this dense fluid is whirlingwith the housing, it will act to urge the vanes 22 to rotate therewith.

The housing rotates at a diilerential speed between the speed of the twoshafts l0 and il. Gradually the driven rotor approaches the speed of thehousing and gradually the housing approaches the speed of the driveshaft 10 until finally the entire assembly will rotate as a unit. Shouldthe load increase, the driven rotor will be retarded and thediflerential speeds will again take eifect. Increase in engine speedimmediately increases the driving torque on the vanes 22 resulting inhigher impingement reaction, higher density reaction, and greater powertransmission.. y

While a specific form of the improvement has been described andillustrated herein, it is desired to be understood that the same may bevaried, within the scope of the appended claim, without departing fromthe spirit of the invention.

Having thus described the claimed and desired secured by Lettersinvention, what is Patent is:

A fluid coupling for transmitting power from a drive shaft to a drivenshaft comprising: a circular housing substantially fllled with fluidconcentrically surrounding the adjacent extremities ofa drive shaft anda driven shaft and free to rotate about and independently of both; adrive hub flxed to said drive shaft within said housing; a plurality offlat drive vanes lying in radial planes about said drive hub; similarflat radial guide vanes projecting inwardly from said housing about theperiphery of said plurality of drive vanes; a driven hub flxed on saiddriven shaft within said housing; and a plurality of flat driven vanesprojecting radially from said driven hub, said driven vanes having aradial length equal to the total radial length of said driving vanes andsaid guide vanes.

CHARLES H. CRABBS.

